Field of the Invention
The present invention concerns a shell and tube heat exchanger comprising heat surface tubes surrounded by a shell, said tubes communicating at one end with an inlet end chamber via a tube sheet and at the other end with an outlet end chamber via a tube sheet, and in the shell side of the heat exchanger there is at least one baffle plate made of flat strips for supporting the heat surface tubes and for guiding the shell-side flow.
Description of the Related Art
The most general solution used for guiding the shell-side flow and for supporting the heat surface tubes is to use segmental guiding/supporting baffles made of a plate. The construction and dimensioning of this kind of baffles has been well discussed e.g. in the TEMA standard (Standard of the Tubular Exchanger Manufacturers' Association). A weakness of these baffles is that in the corners formed by the heat exchanger shell and the baffle plates there are “dead areas”, where the flow speed is low and the heat transfer weak, and these areas also easily get contaminated, and the support provided by them for the heat surface tubes against vibration and buckling is insufficient, especially, when tubes with a small diameter and thin walls are to be used in heat exchangers with a large diameter.
U.S. Pat. No. 5,642,778 discloses another solution for supporting heat surface tubes. There, the heat surface tubes are supported by means of an outer ring and round baffle rods attached thereto in parallel. The desired pitch and supporting of the tubes is provided by changing the thickness and number of the rods of the baffle. When the baffles are positioned crosswise, a four-point support is provided for each heat surface tube. One four-point support requires two or four sequential crosswise arrangements of rod baffles. Weaknesses of this kind of supporting are that a big amount of rod baffles is required for providing a sufficient support, the long rods of the baffles easily start vibrating, which can lead to their breaking, and that pressure loss in the shell-side is relatively high.